Telephone-exchange system



Dec. 29,1925 1,567,283

W. H. MATTHIES TELEPHONE EXCHANGE SYSTEM Filed Feb. 25, 1924 Patented Dec. 29, 1925.

UNITED STATES PATENT OFFICE.

WILLIAM H. MATTI-IIES, OF E EACKENSACK, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed February 2 3, 1924. Serial No. 694,533.

To all whom it may concern:

Be it known that I, WILLIAM H. MAT- THIES, a citizen of the United States of America, residing at Hackensack, in the county of Bergen, State of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which-the following is a full, clear, concise, and. exact description.

This invention relates to telephonegexchange systems and more particularly to such systems employing automatic switches for the establishment of connections.

a In automatic telephone systems, subscrib ers lines are extended to selector switches by means of line switches, which are individual to the subscribers line and hunt for an idle first or district selector, or by line finders, which are each individual to a districtselector and hunt for the calling subscribers line. One type of line finder which may be employed is that disclosed in U. S. Patent 1,237,531 grant-ed August 21, 1917 to A. E. Lundell. This line finder is of the panel type but has no normal position. All idle finders serving the panel are started in response to the initiation of a call and are stopped when one of them findsthe calling line. I

It is an object of the present invention to provide an improved arrangement of line finders ot' the above type.

A feature of the invention lies in means for starting only a portion of the finders having access to a plurality of lines in response to the initiation of a call.

A further feature of the invention lies in the division of the lines, whose multiple terminals form a panel, into groups; the provision of group contacts corresponding thereto; and a starting circuit extended through the corresponding group contacts to each line finder having its brushes engaging terminals in the group of the calling line.

Another feature of the invention lies in the provision of means for extending said starting circuit from one group to the next in the event that there are no idle line finders standing on the group in which the call is initiated.

These and other features of the invention will be more clearly understood from a consideration of the following description in connection with the appended claims and accompanying drawing which shows schematically line finders arranged in accordance with the present invention.

The drawing shows a portion of a line finder panel bank 100 represented by the large rectangle, with the division between groups indicated by horizontal lines, although in practice there would be no visible division between the groups. Three subscribers lines, 101, 102 and 103, are shown, multiple terminals of which appear in the panel bank. Two of these lines, 101 and 102, are represented as appearing in the same group, and the third as appearing in T a different group. Three line finders, 104, 105 and 106 are shown with their brushes occupying various positions on the panel bank. The ccmmutators, 107, 108 and 109, contain the group contacts by means of which the start circuits are extended to the line finders of the group. Line finder 104 is shown standing on the multiple terminals of subscribers line 101 and line finders 105 and 100 standing on the terminals of lines which are not shown. Line finders 104 and 105 are shown with the circuits of their updrive magnets prepared and line finder 100 has the circuit of its downdrive magnet prepared.

Let it be assumed that line finder 10lis busy with line 101. Relays 110 and 111 in the finder circuit and cut-oil relay 115 in the l ne circuit will therefore be energized and relays 112, 113, 114- and the line relay 116 will be deenergized as will be apparent from the following. It now the subscriber on line 102 initiates a call, the removal-oi his re ceiver closes a circuit from battery through the winding of line relay 1.1. inner back contact of cut-ofi' relay 118 over the subscribers line 102, outer back contact of rethe armatureof relay 127.

operates and causes the brush rod to lay 118 to ground. Line relay 117 operates and closes ground to its outer front contact to start the line finders, and battery through resistance 119 to its inner contact to mark the multiple terminals of the calling line in the pane-l bank. A circuit is completed from the groundat the outer contact of relay 117 to battery through the left Wind ng of primary group relay 120. Relay 120 operates and prepares a circuit from ground through the winding of secondary group relay 121 to group contact strips 122, 123, 124, etc., on commutators 107, 108, 109, etc. Since finders 104 and 105 are standing on group 1, this circuit is extended from strip 122 overbrush 125 to the armature of relay 111 and from strip 123 over brush 126 to Since relay 111 is operated, as above assumed, the circuit is not completed over strip 122, but since relay 127 is deenergized the circuit is extended over the back contact of relay 127 to the winding of start relay 128 and battery. Since finder 106 is not standing on group 1,- brush 129-is not engaging strip 124 and no circuit is completed thereover. Relay 128 operates in the above traced circuit-and completes a circuit from battery through the winding of updrive magnet 130, inner lower contact of relay 127, upper contact of armature 142, back contact of relay 132, front contact ofrelay 128 to ground. Magnet 130 move upward in the well known manner. Relay 121 also operates in the circuit of relay 128 and opens the extension of the start circuit leading to primary group relay 133 asso- 7 ciated with group '2. Since brushes 134,

135, 136 and 137 are above the multiple terminals of line 102, they continue to move upward until the brushes reach the top of the pane-l. When this position is reached, brush 138 engages commutator segment 139 closing an obvious. circuit for magnet 131 which attracts armature 142, opening the circuit of the updrive magnet 130 and closing the circuit of the downdrive magnet 140. lllagnets 131 and 141- are so arranged that they act on the common armature 142. Magnet 131 operates whenever the switch reaches the upper limit of its movement and brush 138 encounters segment 139. Magnet 141 operates when the switch reaches the lower limit of its movement and brush 138 engages segment 143. The armature 142 remains in either position until moved out of it by the energization of the other magnet.

The circuit'of the downdrive magnet 140 may be traced from-battery'through the winding of that magnet, lower back contact ofrelay 127, lower contact of armature 142, back contact of relay 132, front contact of start relay 128 to ground. Under the' control of the downdrive magnet, finder 105 is lowered until its brush set reaches multiple terminals 144, 145, 146 and 147 in which line 102 appears before switch 105. At this time brush 134 engages terminal 147 and a circuit is completed from battery through resistance 119, the inner front contact of line relay 117, multiple terminal 147, brush 134, both windings of relay 148, winding of relay 132 to ground. Relay 148 operates closing a short circuit around its high resistance wmding-toso-reduce the potential on terminal 147 and the multiple terminals connected therewith as to prevent any other finder from connecting therewith, and also to permit the operation of relay 132. The energization of relay 132 opens the circuit of downdrive n 1agnet 140 and the finder comesto rest. A circuit 1s also closed from battery through the winding of cut-oil relay 118, terminal 146, brush 135, winding of relay 149, front contact of relay 132, front contact of relay 128 to ground. Relay 149 operates and locks-over conductor 150 to ground in the district selector associated with'line finder 105. In operating, relay 149 extends the talking conductors from subscribers line 102, through terminals 144 and 145. brushes 137' and 1-36'0ver the lower'front contacts of relay 149 to the district selector. At its uppermost contact relay 149 closes a circuit for relay 127 to grounded conductor 150. Relay 127 opens the circuit of relays l28 and 121-and those relays rel-ease. Relay 127 also opens the circuit of both updrive and downdrive magnets to prevent their reoperation. The operation of relay 118 in the circuit above traced, opens the circuit of linerelay 1 17, which relayreleases opening the circuits of relays 148, 132 and 120 all'of which release. The release of relay 120 opens the start circuit of group 1.

Suppose now, that a call is initiated on subscribers line 103. In accordancewith the foregoing description. line finders 104 and 105 are both busy; line finder 106 is idle and the downdrive magnet of that finder is operative as indicated by the position of armature 151. 'Line relay 152 is energized, connecting'battery to its inner armature and thence'to multiple terminals 153, 154, and 155 to mark it to-all line finders. At its outer armature relay 152 con-= nects ground to the left winding of the prnnary group relay 156 of group 4 and that relay operates and prepares acircuit from ground over its armature through the winding of the'secondary group relay 157 of group 4, to the group 4'contact strips 158,159, and 160 associated with finders 104, 105 and 106. None of the-finders 104, 105 or 106 are standing 011 group 4. Hence none of the'brushes, 125, 126and 129, are in contact with strips158, 159 or 160 and the circuit of relay 157 is not completed. Therefore the start circuit is extended from the front contact of relay 156 of group 4 over the back contact of relay 157 of group 4 through the right winding of relay 120 of group 1 to battery. Relay 120 operates and prepares a circuit from ground over. its armature through the winding ofrelay 121 to group contacts 122, 123 and 124. Finders 104 and 105 are standing on group 1 but, since both finders 104 and 105 are busy, relays 111 and 127 are operated and the circuit of relay 121 is open at the upper contacts of these relays. Therefore, the start circuit is extended from the ground at the contact of primary group relay 120 of group 1 overthe back contact of secondary group relay 121 of group 1 through the right Winding of primary group relay 133 of group 2 to battery. Relay 133 operates and prepares a circuit from ground through the inding of relay 161 to group contacts 162, 163, and 164. Since brushes 125 and 126 are in engagement with group contacts 122 and 123, the circuit of relay 161 is not extended beyond group contacts 162 and 163. However, brush 129 is in contact with strip 169,. andsince finder 106 is idle, the circuit is extended over the upper back contact of relay 165 through the winding of start rclay 166 to battery. Relays 166 and 161 operate in this circuit, relay 161 opening its contact to prevent the extension of the start circuit to the primary group relay of the next group, and relay 166 closing the c1rcu1t of the down'dri 7e magnet 167. This c1rcu1t may be traced from battery through the winding of magnet 167, lower back contact of relay 165, lower contact of armature 151, back contact of relay 168, front contact of relay 166 to ground.

Finder 106 moves downward under the control of magnet 167 until brush 129 engages strip 169, brush 129 being of sutficient width to bridge from one group contact strip to the next. Assuming for the moment that finder 106 is the only idle finder at the time, as soon as brush 129 reaches strip 169, the circuit of relays 161 and 166 will be broken and the circuit of magnet 167 will also be opened momentarily. As soon as relay 161 closes its back contact, a circuit is completed for the primary group relay 170 of group 3 from battery through the right winding of that relay over the back contact of relay 161 to ground at the front contact of relay 133. As soon as relay 170 operates, a substitute circuit for relay 166 is closed from ground at the contact of relay 17 0 through the winding of relay 171, group contact 169, brush 129, back contact of relay 165, winding of relay 166 to battery. Relay 166 again operates and closes the previously-traced circuit for downdrive magnet 167 and the finder moves downward over group 3. When brush 129 encounters group contact 160, the circuit of relay 166 is immediately completed through the winding of relay 157 to ground at the contact of relay 156. Relay 157 operates in this circuit and opens the circuit of relay 120, which opens the circuit of relay 133 and this relay in turn opens the circuit of relay 17 0. The finder continues to move downward until its brush set reaches the terminals of line 103. lVhen brush 172 makes contact with terminal 155, a circuit is completed from battery through resistance 173, inner front contact of relay 152, terminal 155, brush 172, both windings of relay 17 4, winding of relay 168 to ground. Relays 174 and 168 operate, relay 174 reducing the potential on terminal 155 and relay 168 opening the circuit of the downdrive magnet. Another circuit is completed from battery through the winding of relay 175, terminal 176, brush 177, winding of relay 178, front contact of relay 168, front contact of relay 166 to ground. Relay 175 operates, opening the circuit of line relay 152. Relay 178 operates and locks to the ground on conductor 179 from the district selector circuit associated with finder 106 and closes the circuit of relay 165 to the same ground. Relay 165 operates, opening the circuit of the drive magnets and the circuit of start relay 166. The release of relay 152 permits the release of relays 174, 168 and 156, the latter relay opening the group 4 start circuit.

At the completion of the call the subscriber online 103 restores his receiver to the switchhook, causing the district selector associated with finder 106 to remove ground from conductor 179. This in turn causes the release of relays 17 8, 165 and 175. The release of relay 175 restores the line relay to the control of the subscribers switchhook; the release of relay 178 opens the talking conductors leading to the district selector; the release of relay 165 places start relay 166 under the control of the group contacts and group relays again and also places the drive magnets again under the control of the start relay.

It will, of course, be understood that a plurality of finders will serve a plurality of lines, i. e., a panel such as panel 100 may contain the multiple terminals of 100 lines,

groups 1, 2, 3 and 4 each numbering 25 lines. Any desired number of finders may be assigned to serve this group of lines, twenty, perhaps being sufficient for average service. It would, therefore, be extremely unlikely that a condition would arise such as described in connection with the operation of finder 106, i. e., that there would be only one idle finder in the entire number serving the bank or that it would be necessary to extend the start circuit over two groups to reach an idle finder. If, however, it should happen that a call were initiated on group 4 and no idle finders were standing 011 that group, it would be necessary for all the idle finders standing on groups 1 and 2to move elf those groups and into group 3 before any finder in group 3 can be placed in service, since the secondary group relays will not make their back contacts to extend the starting circuit as long as an idle line finder is in engagement. with the corresponding group. This would slightly delay the establishment of the connection, but would .be of such rare occurrence as to be practically negligible. \Vhen the last finder moves ofi" group 2, relay 161 would release and'extend the start circuit over its back contact to the winding of relay 170 and relay 170 in operating would start the finders standing on group 3. When the lowest finder on group 3 reached the group contact of group 4, the circuit of relay 157 would be completed immediately so that that finder would be moved to the terminals of the calling line. As soon as relay 1 57 operated, the extended start circuits would all be opened and all other finders would be brought to rest.

It is to be understood that the invention is not to be limited to theuse of commutator strips as groupcontacts. A fifth terminal strip might be added to each set and these strips connected together into groups and thence to the secondary group relay of the particular group. A fifth brush bridging from terminal to terminal will then serve to extend the start circuit to the start relay in the same manner that brushes 125, 126 and 129 do in the present disclosure. Other arrangements applicable to other types of switches are entirely within the spirit and scope of'the invention.

\VVha-t is claimed is:

1. In a telephone exchange system, a plurality of line finders having no normal po sition, a plurality of subscribers lines terminating in said line finders, said lines being divided into groups, a start circuit common to the lines of each of said groups, means controlled over each common start circuit for starting all idle line finders whose brushes are at the time standing within the group to which the start circuit is assigned, and means operative when no idle line finders havebrushes standing within the calling group to render effective the start circuit common to the lines of a subsequent group for starting such idle line finders as at the time have their brushes standing in such subsequent group.

2. In a telephone exchange system, a plurality of line finders having no normal position, a plurality of subscribers lines terminating in said line finders, said lines being divided into-groups, a start circuit common to the lines of each of said groups, means controlled over each common start circuit for starting all idle line finders whose brushes are at the time standing within the group to which the start circuit is assigned,

ing group to render effective in turn the start circuits common to the lines of subse quent groups for starting such idle line,

finders as at the time have their brushes standing in such subsequent groups.

3. In a telephone exchange system, a plurality of line finders having no normal position, a plurality of subscribers lines terminating in said line finders, said lines being divided into a plurality of groups, group contacts equal in number to the number of said groups for each of said line finders, a brush for each of said finders for cooperation with said contacts, a start circuit common to the lines of each of said groups multipled to the corresponding group contacts of each finder, and means controlled over each common start circuit for starting all idle line finders whose brushes are at the time in engagement with multipled group contacts of such start circuit.

4. In a telephone exchange system, a plurality of line finders having no normal position, a plurality of subscribers lines terminating in said line finders, said lines being divided into groups, group contacts equal in number to the number of said groups for each of said line finders, a brush for each of said finders for cooperation with said contacts, a start circuit common to the lines of each of said groups, multipled to the corresponding group contacts of each finder, means controlled over each common start circuit for starting all idle line finders whose brushes are at the time in engagement with multipled group contacts of such start circuit, and means operative when no idle line find-ers have brushes in engagement with the multipled group contacts of the calling group to render effective the common start circuit assigned to a subsequent group of lines for starting such idle line finders as at the time have their brushes .in engagement with multipled group contacts of such subsequent group.

5. In a telephone exchange system, a plurality of line finders having no normal position, a plurality of subscribers lines terminating in said line finders, said lines being divided into groups, group contacts equal in number to said groups for each of said line finders, a brush for each of said finders for cooperating with the contacts thereof, a start circuit common to the lines of each of said groups multipled to the correspondinggroup contacts of each finder, a primary group relay for each of said groups of lines, means for operating a primary group relay in response to the initiation 0" a call in the corresponding group to prepare the start circuit of the corresponding group, means controlled over such start lid circuit for starting all idle line finders whose brushes are at the time in engage ment; with the inultipled group contacts of such start circuit, a secondar group relay for each group of lines operative when no idle line finders have brushes in engagement with the multipled group contacts of said start circuit to cause the operation of the primary group relay of a subsequent group to render effective the common startcircuit assigned to such subsequent group for starting such idle line finders as at the time have their brushes in engagement with multipled group contacts of such subsequent start circuit.

In witness whereof, I hereunto subscribe my name this 15th day of February A. D., 1924.

lVILLIAM H. MATTHIES. 

